webRequest API not working with manifest v3 extension

Question

I'm trying to migrate an extension which uses the webRequest API from manifest v2 to v3 for both Firefox and Chrome. While it works as expected in Chrome, I can't get the webRequest API to work in Firefox with v3. I don't get any error messages, the callback for the onBeforeRequest event just never gets called. Here is a minimal example for Firefox:

v2 working webRequest API

manifest v2
{

    "manifest_version": 2,
 
    "name": "fun",
    "version": "4.0.0",
 

    "background":
    {
       "scripts": ["background.js"],
       "type": "module"   
    },
   
    "permissions":
    [
       "webRequest",
       "<all_urls>"
    ]
 }

background.js

let callbackFilter = { types: ["main_frame", "sub_frame", "xmlhttprequest", "websocket"], urls: ["<all_urls>"] };

console.log("Background script loaded");

browser.webRequest.onBeforeRequest.addListener(() => {
    console.log("Received request event");
}, callbackFilter, []);

v3 not working in Firefox

{
    "manifest_version": 3,
 
    "name": "fun",
    "version": "4.0.0",
 

    "background":
    {
       "scripts": ["background.js"],
       "type": "module"   
    },
   
    "permissions":
    [
       "webRequest"
    ],
    "host_permissions": ["<all_urls>"]
 }